Transmission mixers are employed in optical communication systems when it is desired to transmit the information from one fiber to a plurality of fibers. Mixers are currently available for fiber bundles and generally consist of a mixer rod consisting of a high index of refraction material and containing a low refractive index cladding. A number of optical fiber bundles are attached to each end of the mixer rod to provide optical interconnection between one of the fiber bundles on one side of the rod and all the fiber bundles on the opposite side.
The use of a solid mixer rod for interconnecting between a plurality of input and output fiber bundles results in a certain amount of non-uniformity in the light distribution and light loss due to relatively inconsistent light coupling and mixer losses in a rod of sufficient length.
The purpose of this invention is to provide a transmission mixer having improved light coupling efficiency between the optical fibers and the mixer as well as improved intercoupling efficiency and better uniformity between the individual fibers themselves.